Star Tech Journal

S*TJ JANUARY 1982 5
WILLIAMS
PHILADELPIDA
"DEFENDER"
CPU
* SCHEMATIC * ERRORS
VENDING
BY HOWARD M. SMITH, ARLINGTON, TX
There are several errors in the Williams "Defender" CPU Nideo
Board Logic Diagram, R8570, Sheet 1 of 2. This is the CPU
schematic found in the "Defender" book with the light green
cover.
1 . In the center of the page, just under the CMOS RAM, two
7411 AND gates at 60 are incorrectly drawn as NAND gates.
Also, the gate with pin 6 for an output should have its inputs
numbered 3, 4, and 5 from top to bottom. 2. Pin 18 of the CMOS
RAM at 1 E is shown to be connected to pin 4 of the 7 43 2 at 4R. It
should be redrawn to connect to pin 5 of the same 7432. 3. Just
above the batteries, an inverter at 5B is incorrectly labeled
"7474". It should be changed to read "7404". 4. On the right
side of the page, a 7411 AND gate at 3B has its inputs numbered
1, 13, and 3. Pin 3 should be changed to read pin 2. 5. The crystal
CRl is labeled 120 Mhz. This should be changed to 12.0 Mhz.
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"GALAGA"
IC
* REPLACEMENT
SUBJECT:
LOGIC BOARD IC REPLACEMENT (7400 SERIES)
GAME:
"GALAGA"
1. When replacing a defective IC, use only_ Texas Instrument
type (Ti).
2. If other manufacturers IC's are used it can cause timing
problems.
GOTTLIEB
PROGRAMMED & SOLD
(2516, 271 6-2532, 2732 & Bipolars)
SOFTWARE AND NEW GAME
DEVELOPMENT
*
Program
"VOLCANO"
*
COIL
CHANGE
Change the Firepit Coil from an A-4893 to an A-19300. This
will eliminate the 2N5875 and coil from burning out. See
page 34 of the Volcano instruction manual.
·,
MURPHY'S LAW #311
Any wire cut to length will be too short.
PROMs
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385 Main Street
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